Automatic transfer switches (ATS) are typically used to transfer power between two different power systems. For example, an ATS may be employed to switch between power provided by a utility and power provided by a generator. The ATS provides a means for a user to effectively manage power consumption at a premises by providing the option of switching between the two (or more) power systems. However, such automatic transfer switches typically provide some protection against potentially dangerous situations, such as “back-feeding” of power at the switch location.
To prevent “back-feeding” of power, which may be dangerous to service personnel or others, the automatic transfer switches are commonly of the “open-transition” or “break before make” type. In this type of switch, the connection to one source is opened before the connection to the other source is closed. This type of switch typically employs a mechanical construction or an interlock that makes it physically impossible to provide a connection between the two sources.
The most typical switch employed in this scenario is a multi-pole bi-stable switch. Such a switch is inherently incapable of interconnecting the two power sources. One disadvantage of such a switch is its size and cost. Strong springs are usually employed to provide the force necessary to maintain contact closure pressure required during large fault currents that may occur in electrical distribution systems. If the large currents associated with these faults cause the contacts to part, destructive arcing will occur. These strong springs require large forces to force the switch toggle mechanism over-center, thereby requiring the use of large, expensive electromechanical solenoids to drive the mechanism. Another disadvantage that increases the size and therefore cost is that the contacts used by the different power sources must be physically separated sufficiently to prevent the arcing that may occur at contact opening from extending from one power source contact to the other. Minimizing this arc length requires rapid contact opening which again implies large forces required for movement.
It is with these and other issues in mind, among others, that various aspects of the present disclosure were conceived and developed.